Networking (Chapter 5) Flashcards
Describe LAN
Local Area Network
Connects computers in a single area
Describe WAN
Wide Area Network
Connects the LANs together across large geographical areas
Describe PAN/WPAN
Wireless Personal Area Network
Its just Bluetooth.
What is a defining characteristic of WPAN/Bluetooth?
Its temporary in nature. The networks are formed on an ad hoc basis, meaning two close devices can connect with eachother without a central communication standpoint.
Describe MAN
Metropolitan area network
Generally defined as a network that spans a city or large campus. Similar to WAN, but the difference comes down to who manages it. An IT dept. manages the MAN, and telecommunications the WAN.
Describe SAN
Storage area network
Holds nothing but networked storage devices. It wont have any clients or other servers on it.
What are the biggest advantages to having a SAN?
- Uses block storage (small, manageable, invidividual file chunks)
- They relieve network loads
- Offer fast data access (thanks to fiber)
- Easily expandable
Describe WLAN
Like a LAN but its wireless
May connect through WAPs (wireless access points)
What are the three major components of a network?
Servers
Clients/workstations
Resources
What does a server do?
Provides a link to resources
What is a dedicated server?
A server assigned to provide specific applications or services for the network and nothing else. They require less resources because of this.
What is a non-dedicated server?
A flexible server assigned to provide one or more network services AND local access. They can be used as a frontend workstation for an administrator to work with other applications or services.
An office workgroup server is an example.
How is a workstation defined?
A computer that accesses resources on the network
What is a resource?
Any item that can be used on a network
What is a NOS?
Network operating system
It controls the communication with resources and the flow of data across the network. It runs on the server (Windows Server 20xx).
What are the two resource access models?
Peer-to-peer
Client-server
What roles does a computer play in a peer-to-peer network?
It acts as both the service provider and requestor
What is peer-to-peer model good for?
Small and inexpensive networks
its also called a workgroup!
What is a defining characteristic of a peer-to-peer network?
They have no centralized administration or control
Lacks security
What is the client-server model?
A network that uses one or more dedicated, centralized servers. Administrative tasks and resource sharing occur from this point.
Requires more resources but provides security
Also called domains
What is a defining, beneficial characteristic of a server-based network?
Security is centrally administered
What is a domain controller?
The server that handles login request security
How does account authorization compare between P2P and C-S models?
P2P models require different credentials locally for each machine. C-S models store accounts on the server/domain, so users can login on any machine.
What are the advantages and disadvantages of a bus topology?
+: Cheap, easy to install
-: Difficult to reconfigure, a break disables the entire network
What are the advantages and disadvantages of a star topology?
+: Cheap, easy, more resilient to single cable failure (bus was not)
-:More expensive than a bus
What are the advantages and disadvantages of a ring topology?
+: Efficient, easy to install
-: Difficult to reconfigure, expensive, poor fault tolerance
The only benefit is really that its easy and efficient
What are the advantages and disadvantages of a mesh topology?
+: Best fault tolerance
-: Extremely difficult to reconfigure, extremely expensive
What are the characteristics of a hybrid topology?
Combines the best features of all topologies though still somewhat complex
How does the bus topology work?
A single cable runs to every workstation and each computer shares the same data paths. Messages pass throught the trunk and each workstation checks to see if the message is addressed to it.
You would have to reroute cables if you want to add another computer.
How does the star topology work?
Branches each network device off a central device (hub or switch). This makes it easy to add and remove workstations. The hub is a single point of failure. If it breaks, the whole network goes down. If a workstation fails, the network stays up.
Resilient to cable failure
How does a mesh topology work?
Each device is connected to every other device. Its complex and requires a lot of cable, but gives the advatage of high fault tolerance. Routers can determine the best or alternate paths through the mesh.
They are often used to connect across WANs.
Identify and describe a co-axial cable
Contains a center conductor core made of copper surrounded in a plastic jacket and a braided shield
What connector connects a coaxial cable to a workstation?
BNC
What type of connector is on the end of a coaxial cable?
F-connector (or f-type)
Its used for cable TV.
Why is the twisted pair cable so popular?
Its flexible and inexpensive
What are the two types of twisted pair cable?
Shielded twisted pair (STP)
Unshielded twisted pair (UTP)
UTP is the most commonly used. CAT-7/8 use STP.
What is a Cat 1 cable able to transmit?
Voice only
Only contains two twisted pairs and is used by legacy phone systems. All other categories have four twisted pairs.
What category of cable made the jump from 100 Mbps to 1 Gbps?
Cat 5e
Also has better interference protection with more twists per foot.
5e for extra!
Cat 6 cables transmit at speeds up to ____ Gbps up to a distance of ____ meters.
10 Gbps
55 m
Lowest grade of cable that should be used
What is the difference between a Cat 6 and 6a cable?
6a transmits 10 Gbps up to 100m instead of 55m (6)
What change occurred from a Cat 6a to Cat 7?
It became shielded shielded (still 10 Gbps up to 100m)
An incremental upgrade over Cat 6a
Up to what distance and speed can a Cat 8 cable transmit data?
10Gbps at 100m or
40Gbps at 30m
Distance and speed is the same as the previous Cat 7, but at 30m, it can do 40 Gbps.
Best at short distances
What are the two types of Cat 8 cables?
Class I Cat 8 (RJ-45 and backwards compatible)
Class II Cat 8 (Not RJ-45 or backwards compatible)
Class 2 is alien
How do ethernet naming standards work?
Example: 10Base2
10 is the speed (10 Mbps)
Base is the type of transmission (base or broadband)
2 is the distance in hundreds of meters
–
The* T* in 10BaseT signifies twisted pair.
Base - 1 singal/time, Broad - Multiple singals/time
Identify an RJ-11 and RJ-45 connector used with UTP cables.
4 wires and 8 wires
What speeds are two pairs of wire used for?
What speeds with four pairs?
Two pairs: 100 Mbps or slower connections
Four pairs: gigabit ethernet and faster
What does an ethernet splitter do to a transmitted signal over a four twisted pair cable?
Since the cable can use either two or four pairs, using a splitter will take the signal on two pairs then split it into two separate signals. This limits the speed to 100Mbps.
Identify a punchdown block
Frequently used in analog phone communications
Between the two wiring standards, T568A and T568B, what is the difference in performance?
None
When is a patch (straight-through) cable used?
When connecting different types of devices (computer to switch)
Inversely related: same ends, different devices
When is a crossover cable used?
When connecting like devices togther (computer to computer or switch to switch)
Inversely related: different ends, same devices
What wiring standard does a straight-through cable need to use?
Either, it just has to be the same on each end.
Identify the T568A wiring standard
Gr, Bl, Br divided by orange between each group
Only the bluepair has the solid-colored wire first, otherwise green, orange and brown have the white wire first.
Green first is A
Identify the T568B wiring standard
Instead of green, orange comes first and the green cable becomes the divider between the three colors.
Or, Bl, Br divided by green between each group
Orange first is B
What wiring standard is used in a crossover cable?
T568A on one side and T568B on the other
What is a direct burial cable?
An STP cable with extra waterproofing utilized in underground installations
What kind of cable is immune to interference and wiretapping?
Fiber-optic cable
It uses light instead of electricity.
What speeds is fiber capable of transmitting?
100 Mbps to 10 Gbps over several miles (expensive!)
What are the two types of fiber cable?
Single-mode fiber (SMF)
Multi-mode fiber (MMF)
Which type of fiber cable has a shorter distance and why?
Multi-mode fiber
The light bounces off the walls which causes the signal to weaken more quickly, but does allow for more bandwidth than single-mode.
At what distance can MMF transmit 10 Gbps?
550 meters
MMF transmits significantly shorter than SMF.
Up to what distance can SMF transmit 10 Gbps?
40 klicks (25.85 miles)
SMF transmits significantly longer than MMF.
Speed and distance of Cat 5
100 Mbps at 100 meters
What is the speed and distance of data in a Cat 5e cable?
1 Gbps at 100 meters
What is the speed and distance of data in a Cat 6 cable?
10 Gbps at 55 meters
This is the start of the 10Gbps trend but starts at only 55m.
What is the speed and distance of data in a Cat 6a cable?
10 Gbps at 100 meters
Remember that 6a was a distance improvement from 6 (55m)
What are the three most common fiber connectors?
ST (straight tip), SC (square connector), and LC (local connector)
LC is a mini form factor (think little connector)
What are hubs?
Dummy port replicator that repeats signals to all ports
What is a patch panel?
A large rack-mounted hub (still no network intelligence)
What does a switch do differently than a hub?
Examines the layer 2 header (MAC) of the incoming packet and forwards it to the correct port only
What abilites does a managed switch provide?
Configuring ports, managing traffic, and monitoring for issues
What four features does a switch provide?
Q, R, P, V
QoS - Allows prioritization of certain network traffic
Redundancy - Multiple paths for data to get from point A to B
Port Mirroring - Does what it sounds like
VLANs - One physical switch is segmented into multiple logical networks
What do routers do?
Connects networks together while determining the best path to send data on using routing tables.
What is a firewall ACL?
Access control list
Determines which traffic does and does not get through
If a switch doesn’t support PoE, what device can add it?
PoE injectors (midspan device between the switch and access point)
What is SDN (cloud)?
Software-defined networking
It is a cloud service that virtualizes network hardware.
What is CSMA/CD?
Carrier Sense Multiple Access with Collision Detection
It is a MAC protocol that specifies how network devices should react when two devices try to use the same data channel at the same time and experience a data collision.
What is CSMA/CA?
Carrier Sense Multiple Access with Collision Avoidance
It is used to keep a shared channel free of collision, not detect collisions like CD. NICs listen to the cable to check for traffic and only transmit when the channel is sensed to be idle.
How does a DSL modem provide access to the internet?
Users copper cables through telephone lines
Both DSL and cable make digital connections to the internet
What is an ONT modem and how does it provide access to the internet?
Optical Network Terminal (for fiber)
Turns optical signals into electrical signals to connect to an ISP
What is an unmanaged switch?
A dummy switch
Plug and run without configuration
Is an unmanaged switch a hub?
No.
With a hub, all workstations are on the same wire and every port sees every packet (broadcast).
An unmanaged switch will build MAC address tables and forward traffic intelligently.
Simply put, what is an access point?
Any port where a computer plugs into a network
If you need to run fiber over an especially long distance, which ethernet specification would you use?
10GBaseER or 10BaseT
10GBaseER (or EW too)
This is SMF which can go long distances, hence why MMF wouldn’t work. T is twisted pair.
What is EoP?
Ethernet over power
As long as they are on the same circuit, devices can transmit ethernet signals over power lines.
Which coaxial cable type is recommended for digital signals?
RG-6
RG-59 is for analog signals.
What is a TXT DNS record?
TXT are both human and computer-readable instructions.
They act as a mail authenticator by listing all servers authorized to send messages on the a domain’s behalf.
What is SPF (Sender Policy Framework) and how does it prevent spam?
It authenticates an email server based on its IP address.
The receiving server gets an SPF TXT record of approved IPs for that domain from the sender. If they match, the email goes through.
What is DKIM and how does it prevent spam?
Domain Keys Identified Mail
Hash matching
The outgoing email has a digital header signature that’s encrypted using the server’s private key. The receiving server gets the public key to decrypt the message. If they don’t match, the email is flagged as fake.
What is DMARC and how does it prevent spam?
It combines SPF and DKIM and allows the domain owner to choose what happens if either checks fail.
What is the first server a DNS server contacts if it can’t resolve a domain name?
Root server
What are the three types of IPv6 addresses (cast)?
Unicast: single node on a network
Anycast: small group of systems, message is delivered to closest node
Multicast: message is delivered to a group of computers
Hosts get assigned these, possibly multiple. Its a way of organizing.
What are the rules for shortening IPv6 addresses?
Leading zeros can be replaced with one zero.
Two consecutive groups of zeros can be replaced with “::” but only once.
What is the equivalent of an IPv6 link local address?
APIPA address
Every IPv6 interface is required to have a link local address.
fe80::/10
What devices and identifiers are VLANs and subnets associated with?
VLANs are switches working with MAC addresses.
Subnets are routers working with IP addresses.
Two computers can be on different switches, but can be on the same VLAN.
What does a VPN do?
It encapsulates data to make it more secure through a public network. Appears as a local connection.
What is the IPv6 link local address range?
fe80::/10
How many characters is a MAC address?
12
Can an unmanaged switch intelligently route traffic based on MAC addresses?
Yes
Conversely, a router routes by IP address instead of MAC
Which of these connection types use coax to provide Internet data, voice, and video over the same wire?
A. DSL
B. Cable
C. ISDN
D. Dialup
Correct Answer:
B. Cable
Cable television brought cable into everyone’s home, and now they include voice and Internet services on the same coax cable.
Incorrect Answers:
A. DSL
DSL (Digital Subscriber Line) uses a pair of copper wires to provide Internet access over the same lines as a traditional telephone service.
C. ISDN
ISDN (Integrated Services Digital Network) was the precursor to DSL, and also used a pair of copper wires to provide high-speed dialup Internet service.
D. Dialup
Dialup lines traditionally used the same network as the telephone service, and you would only need a modem on each end of the phone line to provide digital communication.
What are two examples of connectionless protocols?
DHCP
TFTP
What is the transfer speed of FireWire800?
800Mbps
